If thunderstorms hit this summer, airline travel could be a string of hassles and delays.

Many airlines are leaner and operating fuller flights, while some carriers’ pilots and other employees are butting heads with management over executive compensation and labor contracts.

Meanwhile, federal officials are trying to work with an aging air-traffic-control system.

“We’re very concerned about this summer’s airline schedule,” said John Prater, president of the Washington, D.C.-based Air Line Pilots Association International. “I believe it’s going to be as bad as the summer of 2000.”

That year, a pilot slowdown contributed to hundreds of cancellations and delays in the face of one of the busiest summer travel seasons ever.

Prater said airlines have replaced larger planes with smaller ones and increased the frequency of flights for the smaller planes.

“You’ve got more business jets in the air, and you’ve got an air-traffic-control system that has not been modernized. There’s not any more runways. … That combination is not good for our industry,” he said.

Prater’s comments come as the pilots union is urging airlines to come back to the bargaining table to renegotiate contracts and loosen scheduling rules that have increased the number of hours pilots fly.

The airlines, however, say they’re prepared for the summer flying season.

He said software to automatically rebook passengers whose flights are canceled could be ready by this summer. Frontier also doesn’t have the same labor problems that other carriers such as United and Northwest are facing.

For travelers, Hodas said, “I think the same rules apply in the summer as apply to any heavy travel season during the year: Get to the airport in plenty of time; bring a little extra patience.”

United spokeswoman Jean Medina said the carrier is “staffed to meet the travel needs of our customers.”

Travelers are booking long trips for the summer, said Linda Rawlings, owner of Denver travel agency Travel Advocate. She is recommending that summer travelers book itineraries with extra room for delays when going on trips like international cruises.

“There really isn’t any give in the system,” Rawlings said. “If a flight cancels out, you used to be able to say, ‘Oh, well, it’s no problem. We’ll just move you to the next one.’ Well, the next one is full. And none of the carriers want to move you to a different airline.”

Federal Aviation Administration spokeswoman Laura Brown said it’s hard to predict how much of a problem weather will be this summer.

“We know that a lot of the flights are very full … so the passengers have a lot more trouble trying to get on the next flight if their flight gets canceled or delayed,” she said.

United Airlines, for example, set a record for March with its planes 85 percent full on average.

The FAA is broadening a program this year to reduce weather-related delays to planes flying to cities near storms but not directly affected by them.

Prater plans to meet with members of the Air Line Pilots Association in Colorado during a “road show” event Thursday.

Prater said fatigue has been a problem for pilots, who he says can refuse a trip when they are are too tired to fly.

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